1. Field of Invention
This invention relates to deacceleration warning devices for motor vehicles and more particularly to such warning devices manually activated during downshifting deacceleration.
2. Description of the Prior Art
The current fuel conservation trend toward four and five speed compact automobiles has brought about an increased interest in deacceleration through downshifting. Except for sudden emergency stops or complete stops, automobiles may be slowed down adequately by shifting to a lower gear and using the compression resistance of the engine to reduce the vehicle speed. Modern light-weight vehicles require less braking force than the previous heavier cars, and are therefore more suited for down shifting. Further, the greater number of forward gears provides a greater selection of gear ratios or deacceleration forces. Downshifting from high gear to low gear provides a rapid deacceleration, and downshifting between adjacent gears is effective for less urgent reductions in speed. The small gear ratio increment between adjacent gears provides a smoother downshift deacceleration schedule than is possible with the earlier three speed transmission.
In an effort to further conserve the nation's fossil fuels, automobile manufacturers are re-evaluating the fuel thrifty diesel engine for passenger cars. Diesel engines function very well in the downshift deacceleration capacity due to the high compression ratio required to ignite the fuel vapor. The compression ratio in diesel engines is about twice that of a conventional gasoline engine, and therefore generates about twice the compression resistance per cubic centimeter of stroke for deaccelerating the vehicle. Also, larger stroke diesel engines are required to produce the same horsepower.
Slow downshifting between adjacent gears requires a longer deacceleration period than conventional braking, and therefore requires an awareness of remote traffic conditions as well as conditions close by. Skillful downshifters develop an increased driving awareness by automatically noting these remote conditions; and are therefore more prepared for these conditions as their vehicle approaches them. As a result of this increased awareness, downshift drivers encounter fewer surprises and create fewer hazards on the road.
Downshifting deacceleration requires less effort than the conventional two step braking and shifting operation. After downshifting the driver is in the desired lower gear and is not required to perform the second shifting step. Downshifting is a one step operation in which speed reduction and gear change occur simultaneously. Skillful downshifting conserves brake lining, clutch plates, tires and fuel; and requires less driver effort while increasing driver safety.